* { margin: 0; padding: 0; box-sizing: border-box; -webkit-tap-highlight-color: transparent; }

:root {
  --bg: #f8f8fa;
  --card: #ffffff;
  --card-border: #dddde4;
  --accent: #4a6ee0;
  --accent-dim: rgba(74, 110, 224, 0.1);
  --correct: #1a9a45;
  --correct-dim: rgba(26, 154, 69, 0.1);
  --wrong: #d03040;
  --wrong-dim: rgba(208, 48, 64, 0.1);
  --text: #2a2a3e;
  --text-dim: #6b6b80;
  --white: #1a1a2e;
  --safe-top: env(safe-area-inset-top, 0px);
  --safe-bottom: env(safe-area-inset-bottom, 0px);
}

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: 'Inter', -apple-system, sans-serif;
  font-size: 18px;
  overflow-x: hidden;
}

#app {
  max-width: 480px;
  margin: 0 auto;
  padding: 20px;
  padding-top: calc(72px + var(--safe-top));
  padding-bottom: calc(24px + var(--safe-bottom));
  height: 100vh; height: 100dvh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.back-link {
  position: fixed; top: calc(env(safe-area-inset-top, 0px) + 12px); left: 12px; z-index: 999;
  display: flex; align-items: center; gap: 8px;
  text-decoration: none; padding: 6px 14px 6px 6px;
  background: rgba(19, 26, 43, 0.9); border-radius: 12px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.15);
  transition: transform 0.15s;
}
.back-link:active { transform: scale(0.95); }
.back-link svg { width: 28px; height: 28px; border-radius: 6px; }
.back-link span { font-family: 'Inter', -apple-system, sans-serif; font-size: 11px; font-weight: 700; letter-spacing: 1.5px; color: rgba(255,255,255,0.9); }

.hidden { display: none !important; }

/* ── Title Screen ──────────────────────────────────────── */
#title-screen {
  text-align: center; display: flex; flex-direction: column;
  align-items: center; justify-content: center; flex: 1;
  animation: fadeIn 0.5s ease-out;
}

.title-icon { font-size: 64px; margin-bottom: 12px; }
.game-title {
  font-size: 48px; font-weight: 900; letter-spacing: 6px;
  color: var(--accent);
}
.tagline {
  font-size: 14px; letter-spacing: 3px; color: var(--text-dim);
  margin-top: 8px; text-transform: uppercase;
}
.rules-box {
  margin: 32px 0; text-align: left; background: var(--card);
  border: 1.5px solid var(--card-border); border-radius: 12px;
  padding: 20px 24px; width: 100%;
}
.rules-box p {
  font-size: 16px; line-height: 1.8; color: var(--text);
}
.hl { color: var(--accent); font-weight: 700; }
.best-score {
  font-size: 13px; color: var(--text-dim); margin-top: 12px; letter-spacing: 1px;
}

/* ── Buttons ───────────────────────────────────────────── */
.btn-main {
  background: var(--accent); color: #fff; font-family: inherit;
  font-size: 18px; font-weight: 800; letter-spacing: 2px; border: none;
  border-radius: 10px; padding: 0 32px; min-height: 58px; cursor: pointer;
  transition: all 0.15s; text-transform: uppercase; width: 100%; max-width: 340px;
}
.btn-main:active { transform: scale(0.97); opacity: 0.9; }

/* ── Game Screen ───────────────────────────────────────── */
#game-screen {
  display: flex; flex-direction: column; flex: 1;
  animation: fadeIn 0.3s ease-out;
  overflow-y: auto; -webkit-overflow-scrolling: touch; min-height: 0;
}

.game-header {
  display: flex; justify-content: space-between; align-items: center;
  margin-bottom: 8px;
}
.round-label {
  font-size: 14px; font-weight: 700; letter-spacing: 2px;
  color: var(--text-dim);
}
.score-label {
  font-size: 22px; font-weight: 900; color: var(--accent);
  letter-spacing: 1px;
}

.progress-bar {
  height: 4px; background: var(--card-border); border-radius: 2px;
  margin-bottom: 16px; overflow: hidden; position: relative;
}
.progress-bar::after {
  content: ''; position: absolute; left: 0; top: 0; bottom: 0;
  width: var(--progress, 0%); background: var(--accent);
  border-radius: 2px; transition: width 0.3s ease;
}

/* ── Sequence Display ──────────────────────────────────── */
.seq-section {
  display: flex; flex-direction: column;
  align-items: center; justify-content: center; gap: 28px;
  padding: 20px 0;
}

.seq-label {
  font-size: 12px; font-weight: 700; letter-spacing: 3px;
  color: var(--text-dim); text-transform: uppercase;
}

.seq-row {
  display: flex; align-items: center; justify-content: center;
  gap: 8px; flex-wrap: wrap;
}

.seq-num {
  min-width: 48px; height: 48px;
  display: flex; align-items: center; justify-content: center;
  font-size: 24px; font-weight: 900; color: var(--white);
  background: var(--card); border: 2px solid var(--card-border);
  border-radius: 10px; padding: 0 12px;
}

.seq-num.mystery {
  color: var(--accent); border-color: var(--accent);
  background: var(--accent-dim);
  font-size: 22px; letter-spacing: 2px;
  min-width: 56px;
  animation: pulse 1.5s ease-in-out infinite;
}

.seq-num.mystery.revealed {
  animation: none;
}
.seq-num.mystery.correct-reveal {
  animation: none;
  border-color: var(--correct); color: var(--correct);
  background: var(--correct-dim);
}
.seq-num.mystery.wrong-reveal {
  animation: none;
  border-color: var(--wrong); color: var(--wrong);
  background: var(--wrong-dim);
}

.seq-arrow {
  font-size: 18px; color: var(--card-border); font-weight: 700;
}

/* ── Choices ───────────────────────────────────────────── */
.choices {
  display: grid; grid-template-columns: 1fr 1fr; gap: 12px;
  width: 100%; max-width: 320px;
}

.choice-btn {
  background: var(--card); border: 2.5px solid var(--card-border);
  border-radius: 12px; padding: 16px 8px;
  font-family: inherit; font-size: 22px; font-weight: 800;
  color: var(--white); cursor: pointer;
  transition: all 0.15s; text-align: center;
}
.choice-btn:active { transform: scale(0.96); }

.choice-btn.selected {
  border-color: var(--accent); background: var(--accent-dim);
  color: var(--accent);
}
.choice-btn.correct-pick {
  border-color: var(--correct); background: var(--correct-dim);
  color: var(--correct);
}
.choice-btn.wrong-pick {
  border-color: var(--wrong); background: var(--wrong-dim);
  color: var(--wrong);
}
.choice-btn.correct-reveal {
  border-color: var(--correct); background: var(--correct-dim);
  color: var(--correct);
}
.choice-btn.locked {
  pointer-events: none; opacity: 0.5;
}
.choice-btn.locked.correct-pick,
.choice-btn.locked.wrong-pick,
.choice-btn.locked.correct-reveal {
  opacity: 1;
}

/* ── Feedback ──────────────────────────────────────────── */
.feedback {
  margin-top: 20px; text-align: center;
  animation: slideUp 0.3s ease-out;
}
.feedback-result {
  font-size: 20px; font-weight: 800; letter-spacing: 2px;
  margin-bottom: 6px;
}
.feedback-result.correct { color: var(--correct); }
.feedback-result.wrong { color: var(--wrong); }

.feedback-hint {
  font-size: 14px; line-height: 1.5; color: var(--text-dim);
  margin-bottom: 18px;
}

.btn-next { max-width: 240px; margin: 0 auto; }

/* ── Game Over ─────────────────────────────────────────── */
#gameover-screen {
  text-align: center; display: flex; flex-direction: column;
  align-items: center; justify-content: center; flex: 1;
  animation: fadeIn 0.5s ease-out;
  overflow-y: auto; -webkit-overflow-scrolling: touch; min-height: 0;
}
#gameover-screen .btn-main { width: auto; }
.gameover-heading {
  font-size: 32px; font-weight: 900; letter-spacing: 4px;
  color: var(--white); margin-bottom: 16px;
}
.final-score {
  font-size: 64px; font-weight: 900; color: var(--accent);
  margin-bottom: 8px;
}
.final-rank {
  font-size: 20px; font-weight: 700; color: var(--text);
  letter-spacing: 2px; margin-bottom: 24px;
}
.final-stats {
  font-size: 15px; color: var(--text-dim); line-height: 2;
  margin-bottom: 32px;
}

/* ── Animations ────────────────────────────────────────── */
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
@keyframes slideUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.08); }
}

@media (max-height: 667px) {
  .game-title { font-size: 38px; }
  .rules-box { padding: 14px 18px; margin: 20px 0; }
  .seq-num { min-width: 40px; height: 40px; font-size: 20px; }
  .choice-btn { padding: 12px 6px; font-size: 18px; }
}